Search Publications
The Jet of the Quasar 3C 273 at High Resolution.
Davis, R. J.; Meisenheimer, K.; Roeser, H. -J. +3 more
UV Observations of dwarf novae in quiescence - effects of evaporation?
Meyer, F.; Meyer-Hofmeister, E.; La Dous, C.
IUE spectra of dwarf novae in quiescence provide information on the inner part of the accretion disk. In the framework of the evaporation model the mass flow of about 10^-11^Msun_/yr is understood as accretion via a hot corona above the cool inert disk. The UV radiation originates from the transition region between disk and corona, and …
Young nuclei in elliptical galaxies
Sil'chenko, O. K.
Chemically distinct nuclei have been found in the three elliptical galaxies NGC 4564, NGC 4621, and NGC 5576. These nuclei are appreciably younger than the surrounding regions: in the nuclei of NGC 4564 and NGC 4621, the mean age of the stellar population is 8 billion years, and in NGC 5576, it is 3 billion years. Studies of the rotation of the st…
The chemical composition and binarity of beta Crateris
Stickland, D. J.; Kellett, B. J.; Smalley, B. +1 more
A detailed abundance analysis of the bright A-type star betaCrt is presented. It is found that most of the abundances are essentially solar, indicating that the star is not a hot Am star. The only prominent anomalies are an underabundance of Al and overabundances of S, Sr and Ba. The barium overabundance is the most prominent and has important imp…
Acceleration and modulation of energetic particles in the 3-D heliosphere by corotating interaction regions
Simnett, G. M.; Roelef, E. C.
The passage of the Ulysses spacecraft over the poles of the Sun in 1994/1996 has given us a unique insight into the physics of the third dimension of the heliosphere. During the 30-month transit from Jupiter to the south polar pass, the low-latitude heliosphere was dominated by a high speed solar wind stream which produced a corotating interaction…
A Detailed Comparison of Hubble Space Telescope Faint Object Spectrograph and IUE Ultraviolet Spectra of Selected Seyfert Nuclei
Koratkar, Anuradha; Evans, Ian; Pesto, Sharon +1 more
Despite the contributions of the Hubble Space Telescope Faint Object Spectrograph (FOS) to the archive of UV observations of active galactic nuclei, the vast majority of UV reference data were obtained using the International Ultraviolet Explorer (IUE) satellite. These data remain important since they provide historical information about the inten…
Spin and beat phenomena in time-resolved Hubble Space Telescope UV spectroscopy of PQ GEM
Watson, M. G.; Mason, K. O.; Howell, S. B. +2 more
Results of the first low-resolution (6 Angstroms), time-resolved Hubble Space Telescope (HST) Faint Object Spectrograph (FOS) observation of the prototypical strong-field intermediate polar system, PQ Gem, are presented. The lambdalambda1150-2600 continuum light curve is dominated by the 13.9-min rotational signature of the white dwarf at all UV w…
Ulysses: a summary of the first high-latitude survey
Smith, E. J.; Marsden, R. G.
The unique in-situ observations acquired by the scientific instrumentation on board the Ulysses spacecraft have provided, for the first time, a comprehensive, 3-dimensional view of the heliosphere from the solar equator to the poles near solar minimum. Since beginning its journey out of the ecliptic plane in February, 1992, Ulysses has acquired a …
Photometry with a periodic grid. I. A new method to derive angular diameters and brightness distribution.
Mignard, F.; Hestroffer, D.
The interest of observations of point sources with a periodic grid has been recognized for long in astrometry because of the direct relation existing between the position in the sky and the phase of the modulated signal. We investigate in this paper a complementary aspect by showing how observations of an extended stellar or planetary object carri…
ORFEUS observations of SVI, OVI and PV in the stellar wind from the nucleus of NGC 6543.
Grewing, M.; Appenzeller, I.; Krautter, J. +9 more
During the ORFEUS-SPAS (Orbiting Retrievable Far and Extreme Ultraviolet Spectrometer on the Shuttle Pallet Satellite) mission STS-51, flown in September 1993, we observed, to our knowledge for the first time, the central star of the planetary nebula NGC 6543 in the far ultraviolet (90nm-115nm) wavelength region using the University of California,…